Laparoscopic surgery is one type of minimally invasive surgery in which a surgeon uses numerous trocar ports to access and visualize the tissue site of interest within the abdominal cavity of a fully anesthetized patient. The benefits of laparoscopic surgery, as compared to open incisional, abdominal surgery, include less pain, shorter recovery time, less scarring, and lower cost. Another way to access the abdominal cavity, however, is via natural openings (mouth, anus, vagina, urethra) of the body and through the peritoneal lining of the abdominal cavity. Obviously, the size and shape of instruments that may be passed through a bodily lumen in order to perform a medical procedure in the abdominal cavity are greatly restricted due to the anatomical properties of the lumen.
General surgeons, gastroenterologists, and other medical specialists routinely use flexible endoscopes for intraluminal (within the lumen of the alimentary canal) examination and treatment of the upper gastrointestinal (GI) tract, via the mouth, and the lower GI tract, via the anus. In these procedures, the physician pushes the flexible endoscope into the lumen, periodically pausing to articulate the distal end of the endoscope using external control knobs, to redirect the distal tip of the endoscope. In this way, the physician may navigate the crooked passageway of the upper GI past the pharynx, through the esophagus and gastro esophageal junction, and into the stomach. The physician must take great care not to injure the delicate mucosal lining of the lumen, which generally may stretch open to a diameter in the range of about 15-25 mm, but normally has a non-circular cross sectional configuration when relaxed.
One transluminal (passing through the lumen wall of the alimentary canal) procedure is placement of a PEG (percutaneous endoscopic gastrostomy) feeding tube in patients who are unable to ingest food orally. In a PEG procedure, a physician places the end of a specially adapted, flexible tube into the patient's stomach through a percutaneous incision in the patient's abdomen, using a flexible endoscope inserted orally and into the stomach to assist in the placement of the PEG tube. Methods have been developed, including Ponsky-Gauderer (Pull Through) technique, Sacks-Vine (Push Through) technique; Introducer technique, and Button technique. (See Chapter 38, pages 647-662 of “Gastrointestinal Disease, An Endoscopic Approach,” edited by A. J. DiMarino, Jr., S. B. Benjamin, second edition, Slack Incorporated, Thorofare, N.J., 2002, incorporated herein by reference). Placement of a guide wire can include having the guide wire extend through the upper GI tract, with a first end of the wire extending out of the patient's mouth, and a second end of the wire extending out of the percutaneous incision in the abdomen. The first end of the guide wire is then attached to one end of the PEG tube. The physician next pulls the second end of the guide wire to pull the PEG tube through the esophagus and position the PEG tube so that its bulbous end abuts the inner gastric wall, and the rest of the PEG tube extends through the gastric and abdominal walls, and out of the abdomen. (There normally is not a space between the gastric and abdominal walls during this procedure, but it is possible to create a gap by physically lifting the abdominal wall away from the stomach or by insufflating the abdominal cavity with carbon dioxide gas, since this gap is actually part of the abdominal cavity.) While the PEG tube is in place, sometimes for several weeks, the gastric and abdominal walls heal together around the tube, essentially sealing the inside of the stomach from the abdominal cavity.